Boat tripping dockside breaker

[hgunn]

Hi everyone - I have a mid 80s trawler which I have owned for about a year and a half and in the last few months I have been unable to keep the dockside breaker from tripping when on shore power. With everything off, my inverter still trips the breaker after about 5-10 minutes of charging without issue. Has anyone figured out an issue like this before?

I have tried:
- Replacing the shore power inlet on the boat
- Replacing the shore power cord
- Testing for ground fault at the shore power cables inside the boat (roughly 0.005amp net between the positive and neutral)
- Shutting off all circuits and switching on one by one (inverter in and out seem to be the issues)
- Having the marina come out and look at the power pedestal (they said it was all fine)
- Lowering the current draw from shore power (still tripping when only pulling 10amps)

The inverter is a victron multiplus ii and there is a galvanic isolator for the ground to shore power. Any help is so appreciated!

 

[C lectric]

Find and use what is called a SPLITTER. I made my own BUT they can be purchased from electrical supply businesses. Get one that has a higher rating than your potential draw aboard the boat. Also be sure that what you purchase has suitable plugs and sockets OR get someone to make you one using the correct fittings and wire. They are not terribly expensive although maybe not cheap and will likely find service for you elsewhere for .

Then you will need an ammeter that has somewhat more capacity than your electric system. I use the splitter to monitor each device as I plug it in.
THis can tell you if the current draw is higher than you think it is.

To me that is the first step, to know what the REAL current draw is.
If the current draw is too high then you can work on correcting it by using heaters and such that draw less current.

This can tell you if the draw is actually to high or if there is a problem at the breaker box. Then you can approach the marina to correct their supply, new breakers or wiring problems, but you need to find out what your vessel is actually drawing. Does not matter what YOU think it is drawing.

 

[hgunn]

I see that makes sense. I'll have to look into that. I'm curious because it is still tripping with all breakers off except for the inverter which says that it is drawing far below 30amps to charge the batteries. But maybe some power is leaking elsewhere.

Any clue why the boat would be totally fine for about 10 minutes or so and then with no change in devices being turned on or off it trips?

 

[Don L]

I assume what you are calling inverter is a charger

try running the shorepower with the charger off, but some other active load like a hair dryer and see what happens

breakers do go bad

 

[MV Moira]

I'm not going to use the right technical terms here but: A few years back we had a problem in a marina when there was a breaker (ELCI?) on the dock side that would trip when we plugged in. It's a kind of breaker that is only recently required, so marinas with older equipment that haven't been rebuilt won't have it, and won't present a problem.

But in this case, the marina had been recently rebuilt due to storm damage, so there we were.

A marine electrician traced the problem to the connections of an abandoned, unused piece of electrical equipment on the boat. Chopped that off, and the problem went away.

So it may not be a high-amperage flow that's triggering the problem. It may be a micro-amperage flow that causes the fault.

Good luck.

 

[tiltrider1]

I'm wondering if the marina did some sort of upgrade requiring GFI on the Dock. This would explain why the problem is not over current. Just by the data given there appears to be a leakage problem with the boat and that would trip a GFI or ELCI.

 

[Clark]

If your galvanic isolator has a self test feature, it can trip ELCI breakers each time it runs the self test. Some versions, you and just unplug the self test section to see if this helps. Otherwise, it will need to be replaced with a modern failsafe unit.

 

[SteveK]

I see that makes sense. I'll have to look into that. I'm curious because it is still tripping with all breakers off except for the inverter which says that it is drawing far below 30amps to charge the batteries. But maybe some power is leaking elsewhere.

Any clue why the boat would be totally fine for about 10 minutes or so and then with no change in devices being turned on or off it trips?

WAG. 10 minutes for inverter/charger OR charger to heat up the circuit board causing a problem, especially if a fan that was supposed to turn on to cool it does not.
An inverter charger also has a charge rate, or a setting for how much AMPS of the shore supply to use.

 

[Comodave]

First thing I would check is to see if the dock has GFI protected outlets on the power pedestal. If it does then there are a whole lot of things that can cause the breaker to trip even without going over the rated ampacity. It can be a neutral connection on the boat that is incorrect, very common in 1980s boats. They will work on a non GFI outlet but they are dangerous. It could be the inverter that is causing the trip. But first thing is to verify if there is GFI protection on the dock outlets.

 

[O C Diver]

Please take a picture and post it of the shorepower breakers in the pedestal.

Ted

 

[l00smarble]

1. Is the dock breaker an ELCI breaker required by newer electrical code if dock were built or rebuilt in last few years.

We need to know if you a tripping due to overcurrent or from fault current.


An easy way to isolate the issue to your boat or the dock is if you can plug into your neighbors dock receptacle and see if the problem follows or not.

Has the system, as installed now, worked normally on this dock or any dock? Is the Victron or other parts of the on board system new?

 

[hgunn]

Thanks everyone for your help on this. I seem to have found a workaround to the problem by just capping my current draw at 15amps. Enough to keep bilge pumps working and some heat on the boat, but I would love to be able to get back up to the full 30amps. I am not sure if the dock has GFCI for sure, but I am assuming it has at least ELCI because I can measure some ground fault in my shore power with the water heater on. This circuit has been off for the duration of these issues, but there is a still a small (consistent) amount of fault on the shower power.

The harbor has said they checked the pedestal and everything was fine, but I am really not sure how thoroughly they did look at it. I will have to look into the galvanic isolator and see if maybe that test could be causing the fault? That is one of the only pieces of equipment with a more direct connection to shore power than the inverter.

 

[Greg QS]

Go through each circuit 1x1 and see what trips the pedestal. Seems to be you water heater. Is it 220. Check for a bad neutral. A corroded neutral will cause the problem. An element going bad will cause the problem also. It is not the amp draw it is a poor return on the neutral side. Look for anything green on your neutral wires.

 

[twistedtree]

Can you post a picture of the breaker that's tripping? It's important to know if it's a GFCI/ELCI/RCD breaker or not. So far I don't think we know.

Is there a way to plug into a different shore outlet to see if the problem remains the same?

And just for absolute clarity, the breaker that's tripping is the one in the power pedestal on the dock, not any breaker on the boat, right?

Something is definitely wrong and it's worth getting to the bottom of it. Just working around problems like this is what leads to fires and other unpleasant things.

 

[CharlieJ]

@twistedtree What he said!